The answer is that the service group includes only UDP service objects, which is the most likely issue. This is correct because a Palo Alto Networks service group aggregates individual service objects, each defining a specific protocol and port; to match DNS traffic on both TCP and UDP, the group must contain separate service objects for TCP port 53 and UDP port 53. If only UDP objects are present, the security policy cannot match TCP-based DNS queries or zone transfers, causing the rule to fail for that traffic. On the PCNSA exam, this tests your understanding of how service groups for multiple ports and protocols must explicitly include each protocol object—a common trap is assuming a single service object covers both TCP and UDP for the same port number. Remember the memory tip: “One object, one protocol; to cover both, you need two.”
PCNSA Managing Objects Practice Question
This PCNSA practice question tests your understanding of managing objects. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An administrator is troubleshooting a security policy that uses a service group containing both TCP and UDP service objects. The policy is intended to allow DNS traffic (UDP 53 and TCP 53). The rule is not allowing TCP DNS. What is the most likely issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The service group includes only UDP service objects
Option A is correct because the service group must include both TCP and UDP service objects to match DNS traffic on both protocols. If the service group contains only UDP service objects, the security policy will not match TCP DNS traffic (TCP port 53), causing the rule to fail for TCP-based DNS queries or zone transfers. In Palo Alto Networks firewalls, service groups aggregate service objects, and each object defines a specific protocol and port; missing the TCP object means the rule cannot match TCP traffic.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The service group includes only UDP service objects
Why this is correct
Missing TCP service objects prevents TCP DNS from matching.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The rule requires a separate application object
Why it's wrong here
Service objects alone can match DNS traffic on standard ports.
The group itself may be fine, but the member objects might be missing TCP.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume a service group named 'DNS' automatically includes both TCP and UDP, but in Palo Alto Networks, service objects are protocol-specific, so you must explicitly add both TCP and UDP objects to the group.
Detailed technical explanation
How to think about this question
In Palo Alto Networks firewalls, service objects define a protocol (TCP or UDP) and a destination port, and service groups combine multiple service objects. DNS uses both UDP 53 for standard queries and TCP 53 for zone transfers or large responses exceeding 512 bytes. If a service group only includes UDP 53, the firewall will not match TCP packets to port 53, even if the rule is otherwise correct. This is a common oversight when administrators assume a single service object covers both transport protocols.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Managing Objects — This question tests Managing Objects — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The service group includes only UDP service objects — Option A is correct because the service group must include both TCP and UDP service objects to match DNS traffic on both protocols. If the service group contains only UDP service objects, the security policy will not match TCP DNS traffic (TCP port 53), causing the rule to fail for TCP-based DNS queries or zone transfers. In Palo Alto Networks firewalls, service groups aggregate service objects, and each object defines a specific protocol and port; missing the TCP object means the rule cannot match TCP traffic.
What should I do if I get this PCNSA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An administrator needs to create a service group for a custom application that uses TCP ports 1000 and 2000. Which two methods will successfully create a service group that can be used in a single security rule? (Choose two.)
medium
A.Create a service object with port range 1000-2000
B.Create a service object with port 1000 and use an application override
✓ C.Create a service group with two service objects (one for 1000, one for 2000)
✓ D.Create a custom application that includes both ports
E.Create a single service object with port 1000 and a separate rule for port 2000
Why C: Option C is correct because a service group in Palo Alto Networks firewalls can contain multiple service objects, allowing you to combine TCP ports 1000 and 2000 into a single group that can be referenced in one security rule. This enables the firewall to match traffic to either port within the same rule, simplifying policy management.
Last reviewed: Jun 25, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This PCNSA practice question is part of Courseiva's free Palo Alto Networks certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCNSA exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.